1. Field of the Invention
This invention relates to ceiling fans. More particularly, this invention relates to vibration dampers for ceiling fans.
2. Description of the Background Art
Motor driven fans suspended from the ceiling were used extensively in homes in the United States to provide air circulation before the introduction and popularization of central cooling units.
When the energy crisis dawned in the 1970""s, the cost of a kilowatt hour sky rocketed in price and consumers searched for ways to reduce their heating and cooling costs. It has been well established that properly circulated air will raise the overall thermal efficiency of the home air conditioning and cooling system and hence, reduce the cost of maintaining a home at a desired comfort level year round. Thus, ceiling fans were re-popularized in the 1970""s.
Mass produced, low cost ceiling fans have several disadvantages that must be tolerated in return for savings in energy. The lower cost fans are typically noisy and vibrate excessively and the blades visibly sway. The noise and vibration are largely caused by pulsating torques common to all single phase AC motors.
Ceiling fans typically comprise a plurality of fan blades which are rigidly connected to the rotor of an electric motor by means of fan blade brackets integrally formed with or threadably fastened to the blades. In some ceiling fans, the inner rotor rotates within the outer stator of the electric motor as exemplified in U.S. Pat. No. 1,935,314. In other types of ceiling fans, commonly known as xe2x80x9cspinnerxe2x80x9d fans, the rotor constitutes the outer housing of the fan and rotates about the inner stator. U.S. Pat. Nos. 4,621,977 and 4,720,241 disclose such spinner-type fans.
Previous attempts to reduce the noise and vibration originally focused on placing elastomeric grommets about the threaded fasteners which innerconnect the fan blades to their respective fan blade brackets. U.S. Pat. Nos. 5,304,037 and 5,464,323, the disclosures of which are hereby incorporated by reference herein, disclose the use of elastomeric grommets. Similar attempts have also focused on attaching all of the fan blade brackets to a mounting ring and then threadably securing the mounting ring to the rotor through the use of threaded fasteners positioned through elastomeric grommets. U.S. Pat. No. 4,511,310, the disclosure of which is hereby incorporated by reference herein, illustrates the latter embodiment. In both embodiments, the threaded fastener comprises a bolt having a shank portion greater in length than the thickness of the grommet such that the shank prevents compression of the grommet upon tightening of the bolt. Thus, the grommet is freely suspended between the head of the bolt and the rotor. More modem elastomeric rings have been employed such as those disclosed in U.S. Pat. Nos. 4,850,799 and 4,511,310, the disclosures of which are hereby incorporated by reference herein.
The use of elastomeric grommets between the fan blades and the fan blade brackets or between the rotor and a mounting ring to which the fan blades are rigidly connected, have both been favorably accepted in the industry. Notwithstanding, the fan blades may xe2x80x9cwobblexe2x80x9d since the resiliency provided by the freely suspended elastomeric grommets is essentially the same for torsional, axial, and radial forces. Moreover, the elastomeric grommets are difficult to assemble by the do-it-yourself handyman, and are sometimes lost during assembly, thereby resulting in the entire ceiling fan being returned to the store for credit.
Therefore, it is an object of this invention to provide an apparatus which overcomes the aforementioned inadequacies of the prior art devices and provides an improvement which is a significant contribution to the advancement of the ceiling fan vibration damper art.
Another object of this invention is to provide vibration washers for ceiling and other fans which provides torsional damping to dampen the pulsating torque created by single phase electric motors.
Another object of this invention is to provide vibration washers for ceiling and other fans for torsionally damping pulsating torques while minimizing radial and axial movements.
Another object of this invention is to provide vibration washers for ceiling and other fans which may be easily incorporated in existing fan constructions during the manufacture thereof thereby reducing the likelihood that the consumer will misplace the washers during assembly and installation of the ceiling fan.
Another object of this invention is to provide a vibration damper for ceiling and other fans which does not adversely effect the aesthetic appearance of the fan.
The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.
The invention is defined by the appended claims with a specific embodiment shown in the attached drawings. For the purpose of summarizing the invention, the invention comprises vibration washers for ceiling and other fans. More particularly, the vibration washers of the invention interconnect the fan blades with the fan brackets to dampen the pulsating vibrations caused by the electric motor thereby minimizing such vibrations from being transmitted to the fan blades.
The vibration washer of the invention may comprise several embodiments. The principle configuration of the vibration washer of the invention comprises a generally flat annular configuration having a center hole for receiving an upstanding boss extending from the fan blade bracket. The diameter of the hole in the washer is preferably dimensioned so as to be press-fitted over the washer so that it can be installed over the washer at the factory and not be removed from the washer except by significant intentional effort. The washer is seated upon an annular stepped rim portion formed about the boss. During assembly, the ceiling fan blade is positioned over the boss and is secured to the boss by means of a large-headed fastener. In this regard, it is noted that the combined thickness of the washer and the fan blade is slightly greater than the distance between the upper surface of the annular rim portion and the upper surface of the boss such that the washer undergoes a certain amount of compression as the fastener is threaded into the boss. Upon compression, the fan blade is significantly isolated from vibrations due to the elastomeric qualities of the washer.
As noted above, the washer is press-fitted onto the boss during manufacture. In addition to or in lieu of such press-fitting, the vibration washer of the invention may comprise an annular configuration with an inner, central outer depending skirt that fits either into a recess formed in the upstanding boss or around the periphery of the upstanding boss, respectively, of a ceiling fan blade bracket. The skirt of the washer is configured and dimensioned such that it may be press-fitted into the recess of the boss in the case of an inner or central skirt or around the periphery of the boss in the case of an outer skirt during assembly at the factory. The skirt may be annular in configuration or may simply comprise one or more protrusions that fit into the one or more recesses.
In each embodiment, when the ceiling fan is purchased by a consumer for home installation, the washers of the invention are preferably already factory-installed onto the bosses of the fan blade brackets and the only assembly that is required for the fan blades is to screw each of the fan blades to a respective fan blade bracket. The risk of loosing one of the washers during assembly as in the case of the prior art, is therefore precluded.
The foregoing has outlined rather broadly the more pertinent and important features of the present invention in order that the detailed description of the invention that follows may be better understood so that the present contribution to the art can be more fully appreciated. Additional features of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.